Owing to advancing automation and miniaturisation in the area of biotechnology, solutions have been increasingly sought in recent years for the rapid and efficient processing of, especially, minimal amounts of sample. In particular, the use of fully automated, high throughput workstations increasingly demands developments with which very high numbers of samples can be processed in the shortest possible time, while at the same time the smallest amounts of biological material can be detected reproducibly. In this context, the miniaturisation of inter alia filter and separation devices, for example the so-called micro-titre or multi-well plates, are in demand. In addition to the usual 96 well plates, plates with 384 wells and 50 μl volume per well are meanwhile already standard. Moreover, 1536 well plates with volumes of 5 to 10 μl per well have been available for some time.
However, in respect of conventional filter materials for the purification and separation of biopolymers, technical advance has reached its limits with the use of such small wells, especially when the filter and separation materials must exhibit withal very good selective properties and high binding capacities in the purification of biopolymers.
Thus the currently available glass fibre and silica membranes for 96 well plates are of only limited suitability for use in 384 well plates since the filter and separation surfaces would be too small to achieve satisfactory levels of efficiency and binding capacities. Moreover, in addition to increased production expenditure, the punched-out miniature membranes are often too thin and hence too unstable for use in the wells without aids, for example an additional base plate and/or other stabilisation agents that can be inserted into the wells, through which higher production costs are incurred.
In addition, owing to aging, conventional glass fibre and silica membranes loose considerable efficiency, even after a short period of time, so that they are unsuitable for storage over an extended period. Besides, activation of the aged membranes is not only very inconvenient, but frequently not adequate enough to achieve reproducible results.
In this context, in the area of chromatography, monolithic filter and separation materials are currently continually gaining in importance in the preparation of capillary columns. Here, using the so-called sol-gel method, a polymerisable, low-molecular weight compound (sol) is first prepared, which is then converted into aggregated or polymerised material (gel) in polymerisation reactions. The reaction takes place directly in the respective chromatography columns. These methods are, however, solely suitable for capillary columns with a very small diameter (<300 μm), since inorganic monolithic filter and separation material in particular is usually subject to considerable shrinkage, through which a dead volume is created between the monolithic filter and separation material and the separation device, which usually greatly impairs the separation properties of the columns (see DE OS 100 28 572). To remove such dead volumes it has been suggested that after the polymerisation and subsequent aging and drying of the frits, the separation devices are again filled with polymerisation solution and all stages of the preparation method are repeated. However, before a renewed polymerisation can be carried out the aged frit material must first be reactivated with an activation solution, which overall leads to a very time and cost intensive preparation process.
A further disadvantage of these multiply polymerised monolithic frits is also that owing to their construction they are less stable and consequently the abrasion of the monolithic material also increases with increasing diameter of the filter or separation device. In particular, the use in association with pressure devices frequently leads to contamination through increased abrasion, which in turn can lead to interference in the following analysis steps, or even to corrupted results.
In order to overcome the above described disadvantages in the state of the art of known chromatographic separating material, the object forming the basis of the present invention is to provide a stable filter and separation material that allows selective purification and separation of biopolymers as well as an efficient and reproducible processing of a large number of samples, especially in automated and/or miniaturised analytical procedures. The filter and separation material should also be stable in storage and be rapidly utilisable after long storage.